"This is the first model that we know about that you start out with a pretty simple structure for the solar nebula from which planets form, and end up with the giant-planet system that we see," Harold Levison, an astronomer at the Southwest Research Institute (SwRI) in Colorado and lead...
II. 阅读理解Passage 1When we talk about how the Earth and the other planets travel around the sun, we say they orbit the sun.Likewise, the moon orbits the Earth. Many artificial satellites(人造卫星) also orbit the Earth.Satellites can orbit the Earth's equator(赤道) or go over the ...
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When did life start on Earth and how do they know? Life on Earth is believed to have originated around 3.5 billion years ago, as evidenced by the discovery of microfossils and biomarkers in some of the oldest rocks on the planet. These rocks, found in places like Western Australia, provide...
Large alien planets may be born in chaos, NASA's retired exoplanet-hunter finds Rocky planets like Earth are thought to form when dust motes around a nascent star gather to form rocks. Rocks collide, and some stick and grow. "The dust bunnies under your bed grow in a similar way," ...
How did the asteroid belt between Mars and Jupiter form? Why do Jovian planets have more moons than terrestrial planets? What are the main constituents of the Jovian planets? How are supernovae involved in new planet formation? How are rocky planets different from gas planets?
starsarranged in patterns or constellations. The light from these stars has traveled great distances to reachEarth. But what are stars? How far away are they? Are they all the same? Are there otherplanetsaround them? In this article, we will look at the fascinating world of stars. We will...
由第四段中“Hayabusa 2 is special because it sent the sand to Earth without letting it touch the outside air. ”可知,隼鸟 2 号将沙子送到了地球,而没 有让沙子接触到外部空气。 4. B 推理判断题。 由第五段中“The probe has already collected samples and is going to return to Earth in ...
How did the Earth's crust form? How is a volcanic island formed? How is the ocean floor formed? How are planetesimals formed? Where did Earth's water come from? How are new sections of the Earth's crust formed? How are geysers formed?
Only gradually did it heat up, in this view, as uranium and other radioactive elements embedded in its rock decayed and released heat;only gradually did the heat drive water vapor, which had attached itself to rocky minerals in the solar nebula, out of Earth's interior. Erupting in great ...